1. Field of the Invention
The present invention relates to an image forming apparatus which executes corresponding image formation processing in accordance with an image formation request, a control method of same, and a program which causes a computer to implement this control method. More specifically, the present invention relates to an image forming apparatus, and a control method and program for same, whereby, when a manual paper supply unit is connected, image formation is performed preferentially by selecting paper supply from the manual paper supply unit, and furthermore, whereby processing for other print requests is still permitted, even if paper has not been set in the manual paper supply unit after a manual print request has been made.
2. Description of the Background Art
Conventionally, an image forming apparatus which is fitted with copy functions, printer functions, facsimile functions, or the like, often comprises, in addition to a plurality of automatic paper supply units which are generally fitted with paper supply trays or cassettes, a manual paper supply unit in which paper of a desired size can be set. Normally, the manual paper supply unit is provided in order that types of paper which lie outside the specifications of the automatic paper supply units can be supplied and introduced into the main body of the apparatus, in special circumstances. At present, there has been no variation in the basic position with respect to manual paper supply units of this kind.
However, in recent years, the requirement for manual paper supply units has gradually increased, and there have been proposals for technology which not only is able to handle a wide range of paper types, but also allows a plurality of sheets of paper to be supplied continuously from the manual paper supply unit, in a similar fashion to an automatic paper supply unit. In an image forming apparatus fitted with a manual paper supply unit which is capable of supplying a plurality of sheets of paper continuously in this way, if an input image is to be formed onto paper set in a manual paper supply unit, then it is possible to supply a plurality of sheets of paper in a continuous fashion, by specifying the paper size set in the manual paper supply unit, and designating the manual paper supply unit as the paper source.
In an image forming apparatus fitted with a manual paper supply unit of this kind, if the user only specifies the paper size loaded into the manual paper supply unit and has not designated the paper supply unit that is to be the paper source, then the image forming apparatus will execute formation processing for the input image by supplying paper from a paper supply unit that was not intended by the user.
Therefore, in the technology disclosed in Japanese Patent Application Publication No. 2001-235979, the user is prevented from forgetting to make settings, and hence print processing using an unintended paper supply unit is avoided, in addition to which, it is possible to change the paper source rapidly when the user wishes to supply paper from a paper supply unit other than the manual paper supply unit. Therefore, image formation processing using paper supplied from a paper supply unit that was not intended by the user is prevented.
On the other hand, if paper has not been set in the manual paper supply unit, but image formation processing is implemented which specifies the paper size and designates the manual paper supply unit as the paper source, then a problem arises in that processing cannot be continued by automatically switching to another paper supply unit fitted with a paper supply tray loaded with paper of the same size.
In the image forming apparatus disclosed in Japanese Patent Application Publication No. 2001-235979 described above, if the paper size loaded in the manual paper supply unit has been specified for image formation processing, then it is judged whether or not the manual paper supply unit can be designated as the paper source, and if it can be designated as such, then control is implemented to designate the manual paper supply unit as the paper source, and when the designation is completed, a paper selection screen which allows confirmation or changing of the setting of the manual paper supply unit as the paper source, is displayed on an operating section. Thereby, the user is prevented from forgetting to make settings, and the occurrence of image formation processing using an unintended paper supply unit can be prevented.
However, the plurality of operations required, such as the confirmation or changing of the paper loaded in the manual paper supply unit, the setting of the paper size loaded in the manual paper supply unit, the designation of the manual paper supply unit, and the like, create interruptions which cause the image formation process to lose continuity. This has an effect on the formation processing relating to other images and causes a decline in the overall throughput of the image forming apparatus.
Furthermore, since a large amount of operating time is required for paper supply using the manual paper supply unit, then in an image forming apparatus which processes data transferred from a terminal apparatus, such as a personal computer, time-outs occur frequently in the personal computer, or other terminal apparatus. Therefore, data retransmissions occur, increasing the unnecessary communications traffic, placing an extra burden on the network, and adversely affecting other communications operations.
Moreover, if the manual paper supply unit is used frequently, then the time required for operation, and the subsequent interruptions caused to the image processing, will affect the processing of the image forming system and hence affect the overall throughput of the processing.
Furthermore, if the paper loaded in the manual paper supply unit runs out, then the apparatus does not switch automatically to another paper supply unit which is fitted with a paper supply device loaded with paper of the same paper size. Therefore, processing has to wait until the specified paper is loaded, and this means that the operation of the image forming apparatus is halted. Consequently, there remains the problem of negative effects on operational efficiency.
On the other hand, if manual printing is carried out using an image forming apparatus connected to the computer terminals of a plurality of users by means of a LAN, or the like, then firstly, the user sets the prescribed paper in the manual paper supply unit of the image forming apparatus. The user then has to input a corresponding print request at his or her own computer terminal. When the print processing has been completed by the image forming apparatus, the user goes to the image forming apparatus again in order to obtain the printed paper. In this case, the user has to make two round trips between his or her own computer terminal and the image forming apparatus, until he or she can obtain the printed paper. Therefore, in cases where there is a large distance separating the user's computer terminal and the image forming apparatus, there is a risk that the working efficiency of the user will fall.
On the other hand, there is also a method in which the user inputs a corresponding print request at his or her own computer terminal, before loading the prescribed paper in the manual paper supply unit of the image forming apparatus. In this case, the image forming apparatus automatically detects that paper has not been loaded in the corresponding manual paper supply unit, and it outputs an appropriate message and then enters a “standby state”. When the image forming apparatus has entered a standby state of this kind, it will not permit processing of any other print requests, until paper has been loaded in the manual paper supply unit and the processing for the corresponding print request has been completed. As a result, there is a risk that the processing efficiency of the image forming apparatus will fall.